Safe and arm device

ABSTRACT

A rocket launcher firing system wherein a grounding switch is interposed between the intervalometer or selector switches and the firing circuit of the rockets. The system is compatible with present system circuits in all U.S. armed forces planes and helicopters. The grounding switch holds all firing circuits at ground potential until receipt of a positive minimum current from a power source in the aircraft.

United States Patent [191 Taylor, deceased et al.

[H1 3,884,118 [4 1 May 20,1975

[ SAFE AND ARM DEVICE [75] Inventors: Vincent J. Taylor, deceased, late of China Lake, Calif.; by Wayne G. Zellmer, executor, China Lake; Earl E. Beasey, Ridgecrest, both of Calif.

[73] Assignee: The United States of America as represented by the Secretary of the Navy, Washington, DC.

[22] Filed: Nov. 23, 1973 [21] Appl. No.: 418,623

[52] US. Cl 89/1814; 89/1807 [51] Int. Cl F41f 3/06 [58] Field of Search 89/1.8, 1.814, 1.807

[56] References Cited UNITED STATES PATENTS 3,121,369 2/1964 Reeves 89/1.814

3,396,628 8/1968 Nash 89/l.814 3,453,496 7/1969 Wright et a]. 89/].814 3,719,126 3/1973 Elper 8.9/1.814 3,806,683 4/1974 Modene 89/].814

Primary Examiner-Robert F. Stahl Attorney, Agent, or FirmR. S. Sciascia; Roy Miller; Gerald F. Baker [57] ABSTRACT A rocket launcher firing system wherein a grounding switch is interposed between the intervalometer or selector switches and the firing circuit of the rockets. The system is compatible with present system circuits in all US. armed forces planes and helicopters. The grounding switch holds all firing circuits at ground potential until receipt of a positive minimum current from a power source in the aircraft.

6 Claims, 5 Drawing Figures WENKfiwzoma 3 884,1 m

SHEET 10F z POW FIRING SAFETY lNTERVALOMETER SOUR SWITCH SWITCH S8 SAFE AND ARM DEVICE CROSS REFERENCE TO RELATED APPLICATION A rocket launcher system of a type in which the present firing circuit may be utilized is disclosed in assignees prior US. Pat. No. 3,719,120 issued Mar. 6, 1973 to Alton P. Elder and Vincent J. Taylor for Rocket Launching System.

BACKGROUND OF THE INVENTION Certain Rocket Launchers are used for shipping, storing, and air firing of the rockets. For radiationhazard, static-electricity, and strayvoltage protection it is desirable to keep the rocket motor firing squibs grounded until ready to fire the rockets. Systems now in use include grounding plugs on the launchers, Safe- Arm switches, and a grounding arrangement in the launcher intervalometer.

These-systems are effective when properly used, but are subject to misuse, abuse, misunderstanding, and forgetfulness by operating personnel. Any of these situations may render the launcher dangerously unsafe.

Particularly vulnerable areas include:

a. Grounding plugs which must be removed before the launcher is loaded on the Aircraft. This creates the possibility of ungrounded rockets being ignited by stray voltage or RF radiation in the area.

b. Grounding wafers in some intervalometers which can stop in a position that leaves the rockets ungrounded until manual advance of the intervalometer to the Load position. It is also necessary to manually advance these intervalometers from Load to Arm position.

c. Safe and Arm switches now in general use connect the launcher circuitry to the firing circuit from the aircraft when in the armed condition and ground the intervalometer circuit when in the Safe position. The operation of these switches, however, is dependent upon ground crew members and can be overlooked.

The system according to the present invention does not eliminate the safe and arm switch at present but the system may be safely operated without regard to the safe and arm switch. The system does away with the necessity for grounding circuits in the intervalometer and preferably uses a non-grounding intervalometer.

Cockpit intervalometers, for example, as used in helicopters cannot function with a grounding type intervalometer as the circuits are in parallel and, therefore, the grounding intervalometer would place a continuous ground on the circuits which the cockpit intervalometer was attempting to fire. The system according to the present invention allows the launchers to be used with any present U.S. aircraft equipped for rocket launching.

BRIEF DESCRIPTION FO THE SEVERAL VIEWS OF THE DRAWING FIG. 1 is a perspective view of a typical rocket launcher useable with the present invention;

FIG. 2 is a schematic end view ofa 19 round launcher illustrating a typical firing order;

FIG. 3 is a schematic view including a portion of a rocket launcher tube in longitudinal cross section;

FIG. 4 is a schematic diagram of a typical electrical system according to the invention; and

FIG. 4a is an alternate cockpit switch arrangement useable with the schematic of FIG. 4.

DESCRIPTION AND OPERATION The rocket launcher generally designated by numeral 10 in FIG. 1 consists of a main cylindrical body 12 with a nose cone l4 and a tail fairing 16 attached thereto. The body 12 is adapted to be fastened to an aircraft stores racks by means of two lugs 13. Nose cone 14 is broken away to show the rockets l inside of tubes 18. The rocket tubes 18 are enclosed in a fairing or outer covering 17 which also encloses various switches and electrical circuitry which will be elaborated upon below.

FIG. 2 illustrates a typical arrangement of tubes within the outer covering of a typical 19 round launcher. The firing order is from 1a to 9a and then from 1b to 9b with number being fired last or, alternatively by pairs 1a, 1b to 9a, 9b then no. 10.

As shown in FIG. 3, a rocket is held in rocket tube 18 against the rocket stop 20 by means of a detent 22. Detent 22 has a notch 24 which engages a flange 26 on the rocket 15. The rocket tube 18 and the rocket stop 20 as well as the detent 22 are all at ground potential as shown at 28.

A rocket firing contact 30 is pivoted at 32 to a contact support 34 which is mounted on tube 18. The support 34 is insulated from the tube 18, however, by means of a piece of insulating material 36 and insulating bushings 38. Attached to contact member 30 is a push rod 40 to which is connected an electrical conductor 42. Thus, when electrical current is applied to conductor 42, current flows from launcher contact 30 to rocket contact 44 to fire the ignition squib 46 within the rocket 15. The other side of squib 46 is grounded to band 26 of rocket 15 as shown at 48. i

In the conventional rocket launching system now in use a power source 50 and a firing switch 52 are located in the cockpit of the aircraft and a safety switch 54, grounded as shown at 55, and an intervalometer56 are contained within the shell 12 of rocket launcher 10. The intervalometer may be an electro-mechanical or a solid state sequential switching device having a number of outputs 1, 2, 3, n coinciding with the number of rounds in the launcher.

Turning now to FIG. 4, it may be seen that in a conventional cockpit, the power source 50 is connected through an arming switch 51 and firing switch 52 which are connected to components in launcher 10. The arm ing switch 51, for example, is connected to the safe and arm or safety switch 54 according to the present invention and the firing switch output is connected to a grounding switch 58.

Intervalometer 56 is a conventional sequencing switch operated by a solenoid device 60 which causes a switch arm 61 to sequentially supply current to a number of contacts 1, 2, 3, n depending on the number of rockets contained in the system. In prior systems, as shown in FIG. 3, the intervalometer receives current directly from the firing switch through the safe and arm switch in the launcher.

Under the present invention, intervalometer 56 gets its current through the grounding switch 58 only if the grounding switch has been actuated. All of the switches A, B, C, Z are in a grounding position except when solenoid 62 is actuated. Thus, all of the rocket firing circuits are grounded through switches A, B, C, etc, and the intervalometer is grounded through switch Z.

The conventional grounding switch 53 holds ground on the hot side of solenoid 62 as long as safety pin 54 is in place. When pin 54 is removed, current may be supplied through arming switch 51 to solenoid 62 and all contacts of the grounding switch 58 will then be moved to a firing position wherein contacts A, B, C, etc., are connected to contacts 1, 2, 3, respectively of intervalometer 56. Also the switch Z connects to the output of firing switch 52.

Under these circumstances, all that is necessary is to close firing switch 52 and current will be supplied through switch Z to intervalometer solenoid 60. Current will also be supplied to terminal 1 of intervalometer 56 and current then flows sequentially to terminals A, B, C, etc. of grounding switch 58. Current supplied through the successive circuits of grounding switch 58 will actuate explosive squibs 46, 46 etc., until all rounds have been fired.

In some aricraft cockpits, there is a selector switch as shown in FIG. 4a. In these applications the selector switch outputs are connected directly to the corresponding switches A, B, C, etc. in the grounding switch 58. In this case, the intervalometer is by-passed and is ineffectual and, thus, may be removed from the launcher.

In actual practice, a five pin connector (not shown) is provided on launcher for connection to the cockpit arrangement shown in FIG. 4 and a separate 26 pin connector is provided on launcher 10 for connection to those cockpits having an arrangement as shown in FIG. 4a.

From the foregoing, therefore, it may be seen that a safety switching arrangement has been provided which positively grounds all circuits in the launcher and which may not be actuated accept by the direct application of power from the cockpit of the aircraft. In other words, since actuation of solenoid 62 in grounding switch 58 requires a full positive current, stray voltage cannot prematurely fire any of the rockets in the launcher.

What is claimed is:

1. In a weapons firing control system wherein a plurality of weapons may be sequentially or serially fired by electrical current through a plurality of individual circuits, the combination comprising:

A. a source of current;

B. a firing switch;

C. an arming switch;

D. said firing switch and said arming switch being each connected to said source;

E. a plurality of firing circuits;

F. safety switching means connected to said firing switch and having a plurality of two position switches each in one position being connected to respective ones of said firing circuits;

G. said two position switches being biased to the other one of said two positions and said other position connected each of said circuits to ground potential, said switching means being operable for simultaneous movement of said two position switches to said one position thereby connecting said firing circuits to receive current from said firing switch; and

H. electrically operable means responsive to current from said arming switch activating said switching means and thereby moving said two position switches from said other position to said one position.

2. The system of claim 1 including an electrically actuable sequencing switch connected through said safety switching means to said firing switch and one of said two position switches in said other position connecting said sequencing switch to ground; and said one of said two position switches in said one position connecting the activating means of said sequencing switch to receive current from said firing switch.

3. The system of claim 1, including a selector switch connected between said firing switch and said plurality of two position switches for selective application of current to individual ones of said two position switches in said one position.

4. A firing control system for use with airborne rocket launchers having a plurality of electrically grounded rocket tubes which are adapted to carry rockets,

said rocket launcher being provided with electrical circuit means, a plurality of firing circuits and including at least one electrical receptacle for connecting elements of said circuit means with a disconnectable source of power in an aircraft;

safety switching means in said launcher having activating means connectable through said receptacle to said source of power, said switching means comprising a plurality of two position switches each having one position connected to respective ones of said firing circuits,

said two position switches being biased to the other position and said other position connecting each of said circuits to ground potential, said safety switching means being operable for simultaneous movement of said two position switches to said one position for connecting said firing circuits to receive current from said source of power through said receptacle.

5. The system of claim 4 including an electrically ac tuable sequencing switch connected through said safety switching means to said firing switch and one of said two position switches in said other position connecting said sequencing switch to ground; and said one of said two position switches in said one position connecting the activating means of said sequencing switch to receive current from said firing switch.

6. The system of claim 4, including a selector switch connected between said firing switch and said plurality of two position switches for selective application of current to individual ones of said two position switches in said one position.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENT NO. ,11 DATED 20 May WAYNE as ZELLMER, EARL E0 BEASEY, and VINCENT a. TAYLOR 'NVENTOR(5 by WAYNE an ZELLMER, EXECUTOR It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the front page:

after [75] Inventors: delete "Vincent Ja Taylor. .CaI if. and. insert therefor "Wayne G. ZeHmer, China Lake; Ear] E0 Beasey, Ridgecrest; both of Ca] ifo; and Vincent J,, Taylor, deceased, Iate of China Lake, Cahfn by said Wayne G. ZeHmer, executor.

Signed and Scaled this A ttes t:

RUTH C. MASON C. MARSHALL DANN Arresting ()jfice'r Commissioner uflarenrs and Trademarks UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3 4 11 DATED 20 May 1975 WAYNE ea ZELLMER, EARL Ea BEASEY, and VINCENT J. TAYLOR 'NVENTWS) by NAYNE e0 ZELLMER, EXECUTOR It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the front page:

after [75] Inventors:, deiete "Vincent JO Tayior.,.Cai1'f. and insert therefor "Wayne G, Zeiimer, China Lake; Ear] Eo Beasey, Ridgecrest; both of Cahfo', and Vincent Jo Tayior, deceased, late of China Lake, Cah'fo by said Wayne G. Zeiimer, executor.

Signed and Sealed this twen ty-ez'ght D 21y Of October I 975 [SEAL] A ttest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner of Patents and Trademarks 

1. In a weapons firing control system wherein a plurality of weapons may be sequentially or serially fired by electrical current through a plurality of individual circuits, the combination comprising: A. a source of current; B. a firing switch; C. an arming switch; D. said firing switch and said arming switch being each connected to said source; E. a plurality of firing circuits; F. safety switching means connected to said firing switch and having a plurality of two position switches each in one position being connected to respective ones of said firing circuits; G. said two position switches being biased to the other one of said two positions and said other position connected each of said circuits to ground potential, said switching means being operable for simultaneous movement of said two position switches to said one position thereby connecting said firing circuits to receive current from said firing switch; and H. electrically operable means responsive to current from said arming switch activating said switching means and thereby moving said two position switches from said other position to said one position.
 2. The system of claim 1 including an electrically actuable sequencing switch connected through said safety switching means to said firing switch and one of said two position switches in said other position connecting said sequencing switch to ground; and said one of said two position switches in said one position connecting the activating means of said sequencing switch to receive current from said firing switch.
 3. The system of claim 1, including a selector switch connected between said firing switch and said plurality of two position switches for selective application of current to individual ones of said two position switches in said one position.
 4. A firing control system for use with airborne rocket launchers having a plurality of electrically grounded rocket tubes which are adapted to carry rockets, said rocket launcher being provided with electrical circuit means, a plurality of firing circuits and including at least one electrical receptacle for connecting elements of said circuit means wiTh a disconnectable source of power in an aircraft; safety switching means in said launcher having activating means connectable through said receptacle to said source of power, said switching means comprising a plurality of two position switches each having one position connected to respective ones of said firing circuits, said two position switches being biased to the other position and said other position connecting each of said circuits to ground potential, said safety switching means being operable for simultaneous movement of said two position switches to said one position for connecting said firing circuits to receive current from said source of power through said receptacle.
 5. The system of claim 4 including an electrically actuable sequencing switch connected through said safety switching means to said firing switch and one of said two position switches in said other position connecting said sequencing switch to ground; and said one of said two position switches in said one position connecting the activating means of said sequencing switch to receive current from said firing switch.
 6. The system of claim 4, including a selector switch connected between said firing switch and said plurality of two position switches for selective application of current to individual ones of said two position switches in said one position. 